/** * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include <stdio.h> #include "pico/stdlib.h" #include "hardware/gpio.h" /* Our 7 Segment display has pins as follows: --A-- F B --G-- E C --D-- By default we are allocating GPIO 2 to segment A, 3 to B etc. So, connect GPIO 2 to pin A on the 7 segment LED display etc. Don't forget the appropriate resistors, best to use one for each segment! Connect button so that pressing the switch connects the GPIO 9 (default) to ground (pull down) */ #define FIRST_GPIO 2 #define BUTTON_GPIO (FIRST_GPIO+7) // This array converts a number 0-9 to a bit pattern to send to the GPIOs int bits[10] = { 0x3f, // 0 0x06, // 1 0x5b, // 2 0x4f, // 3 0x66, // 4 0x6d, // 5 0x7d, // 6 0x07, // 7 0x7f, // 8 0x67 // 9 }; /// \tag::hello_gpio[] int main() { stdio_init_all(); printf("Hello, 7segment - press button to count down!\n"); // We could use gpio_set_dir_out_masked() here for (int gpio = FIRST_GPIO; gpio < FIRST_GPIO + 7; gpio++) { gpio_init(gpio); gpio_set_dir(gpio, GPIO_OUT); // Our bitmap above has a bit set where we need an LED on, BUT, we are pulling low to light // so invert our output gpio_set_outover(gpio, GPIO_OVERRIDE_INVERT); } gpio_init(BUTTON_GPIO); gpio_set_dir(BUTTON_GPIO, GPIO_IN); // We are using the button to pull down to 0v when pressed, so ensure that when // unpressed, it uses internal pull ups. Otherwise when unpressed, the input will // be floating. gpio_pull_up(BUTTON_GPIO); int val = 0; while (true) { // Count upwards or downwards depending on button input // We are pulling down on switch active, so invert the get to make // a press count downwards if (!gpio_get(BUTTON_GPIO)) { if (val == 9) { val = 0; } else { val++; } } else if (val == 0) { val = 9; } else { val--; } // We are starting with GPIO 2, our bitmap starts at bit 0 so shift to start at 2. int32_t mask = bits[val] << FIRST_GPIO; // Set all our GPIOs in one go! // If something else is using GPIO, we might want to use gpio_put_masked() gpio_set_mask(mask); sleep_ms(250); gpio_clr_mask(mask); } } /// \end::hello_gpio[]

This firmware image was imported from the pico-examples repository. 


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